Radio frequency (RF) devices, such as cell phone transmitters, are becoming increasingly complex due to requirements to operate according to different modes of operation associated with, for example, additional frequency bands, more complex modulation schemes, higher modulation bandwidths, and the introduction of data throughput improvement schemes such as simultaneous RF transmission and/or reception within a same or different, but closely spaced, bands or channels within a band (e.g. voice, data), and aggregate transmission wherein information is multiplexed over parallel RF transmissions.
In order to support such different modes of operation, use of mode specific amplifiers may be one option. However, as the number of modes increases, such an approach may become too costly and unpractical. For example, considering the high number of different frequency bands that an RF device, such as a cell phone transmitter, may need to support, the traditional approach of adding band specific narrow band amplifiers for each of the supported frequency bands may be prohibitive due to its high cost and required large physical size. Rather, current implementations support the high number of different frequency bands by way of a combination of one or more wide band amplifiers, each capable of supporting several frequency bands, and narrow band filters that are selectively coupled at the output of the wide band amplifiers based on a selected band of operation. Although such configuration solves problems associated with usage of band specific narrow band amplifiers, performance of the RF device as measured, for example, by a power output, or power added efficiency (PAE), may be degraded. It is therefore an object of the present disclosure to provide a solution to the traditional approach of using mode specific amplifiers while reducing a performance degradation associated with the provided solution.